Sounding apparatus



SOUNDING APPARATUS Filed May 2, 1936 l7 2/ e INVENTQR Home reaauw 37 lI" -L I o L 67 3.; 63 ATTORNEY Patented Oct. 25, 1938 UNETED STATES FATEOFFICE 9 Claims.

This invention relates to a sounding apparatus for determining actualaltitude of aircraft above the ground or water when it is obscured fromView of the pilot.

In present navigation practice, aircrafts are provided with instrumentswhich indicate altitude relative to sea level, however, these types ofinstruments are of little use to a pilot in making a blind landing, ashe is not concerned with his height above sea level but with his actualdistance above the ground over which he is navigating. It is true thathe knows the approximate elevation of that section above sea level andcan approximately calculate the distance to the ground in that generallocality, but this is not sufiicient as the ground levels within a shortdistance may vary as much as several hundred feet, and while theaircraft may be at the calculated distance above sea level it may bewithin a few feet of crashing into the ground.

It is, therefore, the principal object of the present invention toprovide an apparatus wherewith a pilot can readily ascertain thedistance between his aircraft and the ground.

It is also an important object of the present invention to provide anapparatus whereby the pilot is kept informed progressively with his.descent.

In accomplishing these and other objects of the invention, I haveprovided improved details of structure, the preferred form of which isillustrated in the accompanying drawing, wherein:

Fig. 1 is a perspective view of an airplane equipped with a groundcontacting apparatus embodying the features of the present invention.

Fig. 2 is a detail perspective View of the ground contacting shoe.

Fig. 3 is a section through the contacting shoe,

particularly illustrating the switch for closing the circuit to theheight indicating apparatus carried in the airplane.

Fig. 4 is a detail perspective view of the reeling drum, heightindicator and its operating motor showing the wiring connectionstherefor in diagram.

v Fig. 5 is a section through the ground contacting shoe on the line 5-5of Fig. 3 to illustrate the stream-lining thereof.

,50 Fig. 6 is a crosssection through thelowering cable for thecontacting shoe.

; Fig. 7 is a detail elevational view partly in cross-sectionillustrating the prong and socket .membersof the cable in connectedcondition. 335 Fig. 8 is a detail perspective View of the prong andsocket members of the cable in separated condition and particularlyillustrating the frangible wire for normally maintaining the cable inconnected condition.

Referring more in detail to the drawing: -5

l designates an aircraft in which is mounted a reeling apparatus 2,including a supporting frame 3 having spaced bearing bracketsd and 5 forrotatably mounting a shaft 6. Fixed to the shaft 6, intermediate thebearing brackets, l0 is a reel 1 including a drum 8 having spaced endflanges 9 and i9. Wound on the drum, between the flanges-S and i0, is alowering cable H having one endextending through the end flange IE3 andconnected with a commutator I2 15 also keyed on the shaft 6 androtatable with the reel.

Fixed to the other flange 9 of the reel is a brake drum l3 on which ismounted a brake band 44 having one end fixed to the frame by 20 abracket l5 and its opposite end terminating in an ear It to which isconnected an actuating 'rod I? that is slidably mounted in the bracketl5, and has a head I8 on its outer end. A coil spring is is sleeved overthe rod and has one '25 end bearing against the bracket I5 and itsoppoposite end against the head l8 to normally retain the brake band ingripping contact with the drum [3 for preventing rotation of the reel.The other end of the cable is wrapped about a [30 sheave 20 fixed on acounter-shaft 2! rotatably" mounted in bearing brackets 22 on thesupporting frame 3. i

Coupled with one end of the counter-shaft is a flexible shaft 23 havingits opposite end con- 35 nected with a distance indicator 24 that is 10-cated in the airplane in convenient View of the pilot. The indicatorincludes a dial 25 having graduations preferably marked in feet, andmovable over the dial under actuation of the fiex- 40 ible shaft is apointer 26 that is normally at" zero when the contact cable is wound onthe reel, but which moves over the scale as the cable is unwound fromthe reel over the sheave to indicate the length of cable that is paidtherefrom when ascertaining the distance of the air" plane above theground, as later described.

The free end of the contact cable extends through a suitable opening inthe bottom of the aircraft and carries a ground contacting sh0e50 21that is adapted to automatically set the reel in operation to wind upthe paid out cable when the shoe makes contact with the ground. The shoeis preferably stream-lined and has a rounded contact face 28 and afeathered rear edge, 29

to hold the rounded face in a straightaway position for contact with theground. The shoe is pivotally mounted on a cross-pin 30 that is carriedby a switch-block 3| fixed to the end of the cable.

The pivotal movement of the shoe relatively to the switch-block ismaintained within a restricted limit by means of spaced stop lugs 32 and33 which are adapted to engage the front and rear faces of the block.The lug 33 is of longer length than the lug 32 to constitute aswitch-arm for closing circuit through spaced contacts 34 and 35 thatare carried by the switchblock and attached to conductors 36 and 31incorporated into the lowering cable.

The lowering cable is preferably formed of insulating material in whichthe electrical conductors 36 and 31 are imbedded to prevent shortingthereof and contact with metal parts over which the cable might'bedrawn. The conductors extend the full length of the cable and have theirother ends connected to contact rings 38 and 39 of the commutator whichare engaged by brushes 40 and 4| carried by the frame, as shown in Fig.4. A r

42 designates a motor that is mounted on the frame 3 and has itsarmature shaft 43 provided with a pinion gear 44 meshing with a gear 45having driving connection with a gear 46 on the shaft 6, so that whenthe motor is energized the shaft is rotated to rotate the reel to windthe cable thereon. The motor may be supplied with current from asuitable source, such as a battery 41, having one terminal connectedwith the brush 40 through a conductor 48 and its other terminalconnected by a conductor 49 leading to one of the terminals of themotor. The other terminal of the motor is connected by a conductor 56with the conductor 48.

Connected with the conductor 50 is a conductor 5| leading to a switch 52having an arm 53 that is adapted to be engaged by a pin 54 on a suitablysupported gear 55 that meshes with a pinion gear 56 on thecounter-shaft. The other contact of the switch 52 is connected to theconductor 48 by a conductor 51 which also connects with the brush 4| bya branch 58. The gear 55 is driven by the counter-shaft pinion gearincidental to pay of the cable over the sheave 20 so that every time thegear 55 has made one revolution in an anti-clockwise direction the motorcircuit is broken to stop operation of the reel. The gears 55 and 56 areof such size that a fixed number of feet of cable passes over the sheaveduring each period of motor operation, for example tenv feet.

The motor is so geared that the cable is wound in almost immediatelyupon closure of the circuit by the ground contacting shoe so that theshoe will not drag upon the ground.

As soon as the contacting shoe is raised from the ground the weightthereof will cause it to pivot on the pin 30 to break circuit throughthe contacts 34 and 35, however, I provide means for keeping the motorcircuit closed until it is broken by the switch 52, upon contact of thepin 54 with the switch-arm 53. This is accomplished by conmeeting asolenoid switch 60 across the conductors 48 and 50 and in parallel withthe'switch on the contactingshoe. The solenoid 6| of the switch isenergized immediately upon closure of the motor circuit through theconductors 36 and 31. This is accomplished by connecting the solenoidwith the conductors 49 and 64, thus when the circuit, includingconductors 36 and 31, is closed by the ground contacting shoe, currentflows from the battery 41, through the conductor 48, brush 4!),con-ductor 36, contacts 34 and 35, conductor 31, brush 4|, and throughthe solenoid 6|, back to the battery, through the conductor 49 to closethe switch 66 so that current can then flow from the battery 41 throughthe conductor 46, switch 66, conductor 50, to the motor and back to thebattery through the conductor 49.

Upon closing of the switch 60 there is established another path for thecurrent from the battery through the solenoid, by way of the conductor48, switch 66. conductors 59 and 5|, switch 52, conductor 57 to thesolenoid, and through the solenoid to the conductor 49 back to thebattery, to retain the switch 69 in closed condition until the pin 54strikes the arm 53 to open the switch 52. Upon opening of the circuit,including the switch 52, the circuit through the solenoid is broken toopen the switch 60. Since the ground contact switch has previouslyopened and the switch 66 is now opened, the motor circuit is broken tostop wind-up of the reel and the reel will remain idle until thecontacting shoe again makes engagement with the ground or otherobstruction. Immediately upon subsequent engagement of the contact shoe,the circuit is again closed through the motor to continue operationthereof until the circuit is again broken by the switch 52. The reel isthus caused to reel in the cable a fixed amount upon each contact of theshoe with the ground. I

In order to release the brake and allow rotation of the reel, as abovedescribed, whenever the motor is energized, the conductor 49 isconnected with the winding of a brake solenoid 62 by a conductor 63. Theother terminal of the solenoid is connected by a conductor 64 with theconductor 50, so that when either the switch carried by the contact shoe2'! or the switch 60 is closed current flows through the brake solenoidto energize the armature thereof for releasing the brake band againsttension of the spring that holds it in gripping engagement with thedrum, the armature 65 of the solenoid being connected to the ear I6, asclearly shown in Fig.4.

.In order to reel in the cable independently of the cable switch, Iprovide a manually operated switch 66 that is connected to the conductor46 by a conductor 61 and with the conductor 53 by a conductor 68. rentflows through the solenoid coil 6| tohold the switch 69 closed andefiect energization of the motor. As this switch is manually closed,current will be continuously supplied to the motor as long as it is heldclosed and the switch 52 is not efiective in breaking the motor circuit.

In order to release the brake so as to allow paying out of the cable,the brake armature is provided with another solenoid winding 69 that isconnected in circuit with a battery 16 whereby current is supplied tothe coil upon closing of a switch When this switch is closed, thesecondary solenoid winding 69 is energized to release the brake andallow paying out of the cable.

It is desirable that the cable hang as near plumb as possible, and I,therefore, attach a weight '52 to the cable at a relatively shortdistance above the contact shoe 21. When the'shoe makes contact with anobject or the ground, the portion of the cable depending below theweight is free to flex or swing in an upward direction incidental to theimpact with the point of weight attachment acting as a pivot. The shoeis, therefore, quicker to respond to the reaction or the When thisswitch is closed curimpact and is thrown clear of any object tending tofoul the cable.

To prevent damage to the aircraft in case the cable should foul, I formthe cable into sections that are connected by a coupling device 13comprising plug and socket members 14 and 15 that are respectivelyconnected with the cable sections, the plug member being on the lowerend of the upper section and the socket member on the upper end of thelower section. The socket 15 has sleeve contacts 16 for receiving prongsTI on the plug member to make electrical connections between thecontained conductors. The socket member also has a tongue 18 engaged ina recess 79 of the plug member the plug member being secured in thesocket by means of a frangible wire 80extending through alignedapertures in the tongue and socket members as shown in Figs. 7 and 8. Itis thus obvious that should the lower section become entangled with someobject, pull exerted by the aircraft on the cable will fracture the wire80 and cause the connecting members to pull apart. When this separationoccurs a spring contact 8i that is suitably mounted on one of the prongsfor normal extension across to contact with the other prong and which isordinarily retained from bridging across the prongs by the tongue 18will be released to assume its normal position for shorting theconductor by bridging the prongs to complete a circuit therethrough andeffect reeling in of the remaining part of the cable. It is desirable towarn the pilot when the sections part and for this reason I extend oneof the cable conductors to the indicator and connect therein a signallight 82 which will burn continuously after the break occurs. Thissignal light will also flash upon each ground con-" tact of the shoe 29but as soon as the circuit through the shoe switch is broken the lightwill cease to burn. The pilot may thus be advised as to functioning ofthe ground contact shoe whenever it is in use.

In using a device constructed as described, and I assuming that thepilot wishes to ascertain his distance above the ground, as when makinga blind landing, he will close the switch II to effect energization ofthe secondary solenoid winding 69 for releasing the brake band fromcontact with the reel drum. Upon release of the brake the cable isautomatically paid out under pull of the weight 12 plus the weight ofthe shoe. Paying out of the cable rotates the counter-shaft and resultsin moving the pointer over the dial to indicate the amount of cable paidout. When the cable has been completely paid out and no contact has beenmade with the ground, the pilot knows that he is at an altitude greaterthan the length of the cable, or in the illustrated instance, more thanthree hundred feet above the ground. He will then lower his craft untilthe contact shoe engages the ground. At this time he will be threehundred feet above the ground.

Immediately upon engagement of the contact shoe with the ground or otherextraneous objects,

7 the circuit is closed thereby through the conductors to effectoperation of the motor. Upon energization of the motor the reel will berotated, winding up the cable until the pin 54 engages the switch-arm tobreak circuit through the solenoid coil 6|, whereupon the switch 60 isopened to break the motor circuit and stop rewinding of the reel. Uponbreaking of the circuit the spring I9 comes into play to apply the brakeband for holding the reel. The pilot will then lower his craft untilanother ground contact is made,

whereupon the circuit is again closed to wind'in the reel another fixedamount as controlled by the timing of the pin 54.

The aircraft will thus be lowered in progressive stages as gauged by thecable, until the ground is in sight or until the pilot knows that he iswithin a safe distance of the ground to land. By observing the indicatorhand 26, the pilot can readily observe his height above the ground .uponeach contact of the shoe therewith. He is thus kept Warned of hiselevation relatively to the ground from the time that the first contacthas been made, and can lower his craft accordingly.

Fromthe foregoing, it is obvious that I have provided an apparatuswhereby a pilot can readily ascertain his elevation above the groundwhen it is necessary for him to make a blind landing, and which will aidhim in making a safe descent.

What I claim and desire to secure by Letters Patent is:

1. In a sounding apparatus, a reel, supporting means rotatably mountingthe reel in a given position, a sectional cable having one end engagedwith the reel, a contact device carried by the other end of the cable, amotor for actuating the heel to wind the cable thereon, a source ofcurrent supply for the motor, conductors incorporated in the cable andadapted to complete a circuit through the contact device, motor andsource of current supply incidental to engagement of the contact devicewith the ground, means mounted in the connecting ends of the cablesections adapted to allow disconnection of the lower section of thecable upon entanglement thereof with an object on the ground, and signalmeans actuated through said conductors incidental to disconnection ofthe cable sections.

2. In a sounding apparatus, a reel, supporting means rotatably mountingthe reel in a given position, a sectional cable having one end engagedwith the reel, a contact device carried by the other end of the cable, amotor for actuating the reel to wind the cable thereon, a source ofcurrent supply for the motor, conductors incorporated in the cable andadapted to complete a circuit through the contact device, motor andsource of current supply incidental to engagement of the contact devicewith the ground, and means mounted in the connecting ends of the cablesections adapted to allow disconnection of the lower section of thecable upon entanglement thereof with an object on the ground.

3. In a sounding apparatus, a reel, supporting means rotatably mountingthe reel in a given position, a sectional cable having one end engagedwith the reel, a contact device carried by the other end of the cable, amotor for actuating the reel to wind the cable thereon, a source ofcurrent supply for the motor, conductors incorporated in the cable andadapted to complete a circuit through the contact device, motor andsource of current supply incidental to engagement of the contact devicewith the ground, means mounted in the connecting ends of the cablesections adapted to allow'disconnection of the lower section of thecable upon entanglement thereof with an object on the ground, signalmeans, and means on the upper cable section adapted to short theconductors upon disconnection of the lower cable section therefrom foractuating the signal means.

4. In a sounding apparatus, a support, a contact device, means forlowering the contact device relative to the support, means for raisingthe contact device from its lowered position, means indicating thedistance of the contact device from the support, safety means in thelowering means adapted to allow disconnection of the lower portionthereof upon entanglement of the contact device with an object below thesupport, and means in said safety means operable incidental todisconnection of said portion of the lowering means for actuating saidraising means;

5. In a sounding apparatus, a reel, supporting means rotatably mountingthe reel in a given position, acable having one end engaged with thereel and having a switch block on its other end provided with contacts,a contact device pivotally mountedon the switch block, said devicehaving a lateral extension normally maintaining the same out ofengagement with said switch block contactsa motor for actuating the reelto wind the cable thereon, a source of current supply for the motor, andconductors incorporated in the cable connected with the switch blockcontacts and completing a circuit through the contact device, motor andsaid source of current supply incidental to pivotal movement of saidextension into engagement with said contacts in response to engagementof the contact device with the ground.

6. In a sounding apparatus, a reel, supporting means rotatably mountingthe reel in a given position, a cable engaged with the reel, a shaftrotatably supported on the reel supporting means and engaged with thecable, means connected with the shaft and movable in response torotation of the shaft, a contact device carried by the cable, a motorfor actuating the reel to wind the cable thereon, a source of currentsupply for the motor, a switch connected with the motor and adapted tobe engaged by said movable means upon a predetermined number ofrevolutions of said shaft for deenergizing the motor, and conductorsincorporated in the cable adapted for connecting the contact device incircuit with the motor and said current supply to actuate the reelincidental to engagement of the contact device with the ground.

7.-In a sounding apparatus, a reel, supporting means rotatably mountingthe reel in a given position, a cable engaged with the reel, a shaftrotatably supported on the reel supporting means and engaged with thecable, means connected with the shaft and movablein response to rotationof the shaft, a contact device carried by the cable, amotor foractuating the reel to wind the cable thereon, a source of current supplyfor the motor, a switch connected with the motor and adaptedto, be,engaged by said movable means upon a predetermined number of revolutionsof said shaft for deenergizing the motor, and an indicator drivenfromsaid shaft to register the length of cable paid out.

8. In a sounding apparatus, a support, a con; tact device, means on thesupport for raising and lowering the contact device relative to thesupport, and means on the support engaged with and actuated by saidraising and lowering means adapted to control raising of the contactdevice and limit the upward movement of same to a plurality ofpredetermined stages.

9. In a sounding apparatus, a support, a contact device, means on thesupport for raising and lowering the contact device relative to thesupport, means on the support engaged with and actuated by said raisingand lowering means adapted to control raising of the contact device andlimit the upward movement of same to a plurality of predeterminedstages, and means forming part of the raising and lowering meansallowing disengagement of the contact device therefrom in response torestraint on the device greater than normal impact with the ground.

HOIWER L. BREDOUW.

